"The problem with using the PID controller is that the thermocouple or RTD probe (thermometer) is placed at the top of the still head, not in the boiler, you would have to continually (manually chasing) the settings for heat input depending on mash, alcohol content, etc. and, so what, the mash will boil at what ever it wants to anyway!
You cannot use this controller for this application properly. The PID controller is designed to have a thermocouple directly placed in a liquid, not vapour! The controller uses a On/Off approach to applying heat, it is not a constant heat source, maybe turned down, but CONSTANT heat is what we need! Not On/Off cycled output!
I will try to use my PID, however, I will lose purity and may not get my column to equilize using this method, even by changing one element out to a 1.5kW element. I what to experiment a little and see if I can get the controller to keep the second element on full blast, but at half the wattage! and use the Alarm 2 setting to shut down the boiler.
If I do add a Variac, I will keep the PID controller (room permitting) in my electrical enclosure and use output 1 (the 3.0kW element) to ramp the mash to boil and then have the PID send a 4-20 mA signal to the Variac for manual control of the 1.5kW element for constant heat. Not cycling!
From what I've been reading, this controller (PID) is great for grain infused mashing, but not distilling your final product! This is different.
I spent the last four months designing, reading and making my still, and I still made mistakes, It Is What It Is! and if all else fails, I know a Variac (SCR) controller will work--hands down-- even will out the PID!
I think I'm just as new as you and I'm no pro at distilling, but I hope the info helps!
BH"
